


A Sun's Hidden Shadow

by Meian_of_Yin_Yang



Series: Matters of the Soul [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Other, Underfell Sans, Underswap Sans
Language: English
Status: In-Progress
Published: 2016-07-19
Updated: 2018-03-21
Packaged: 2018-07-25 08:56:05
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 8,467
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7526446
Author URL: https://archiveofourown.org/users/Meian_of_Yin_Yang/pseuds/Meian_of_Yin_Yang
Summary: <blockquote class="userstuff">
              <p>A little ray of sunshine is born. His family loves him and he loves them back. He gets to spend time with them and have fun, even get a little spoiled. Everything is perfect.</p><p>Or is it?</p><p>There's always a shadow hiding where ever there is sunlight.</p>
            </blockquote>





	1. A New Day is Born

**Author's Note:**

> NOTE: I am NOT ending AFiM at chapter 8. I will be working on the other chapters whenever I feel like it. The reason? Because I'm fricking obssessed with my new OTP, Daydream and it's so fricking kawaii that I squeal just thinking about it!

`Hex is this type.`  
Sasha is normal  
Sarah is this type.  
**Onyx is this type.** )

* * *

 

  
  
Cries of pain echoed from upstairs, causing the large gold-toothed skeleton to flinch as another crack appeared on his body. It was taking everything he had just to stay put on the couch with his twin daughters and step-son. He felt a small hand grab his sleeve and looked down to see the pink eyes of the youngest twin staring up at him with worry.  
  
"Daddy, is Mommy gonna be okay?" She asked. The skeleton forced himself to smile.  
  
"Y-yeah. Mommy's gonna be fine. Undyne and Tori are gonna make sure of that." Looking over towards the stairs, he sent out a silent plea. _God, please let Swap make it. Please._ Soon the cries stopped and everything went silent. Footsteps could be heard coming down the stairs and a tall fish-like female monster, with long red hair up in a ponytail, glasses, and wearing a doctor's uniform, walked into the living room with a rather solemn looking expression.  
  
"You three stay put." The skeleton said, then got up and walked over to the other monster.  
  
"Undyne, how's Swap? Is he okay?" He asked, keeping his voice low so the kids wouldn't hear him. She hesitated for a minute before answering.  
  
"Its....hard to say. They're both extremely weak right now. I called an ambulance so we can get them to the hospital." Undyne replied.  
  
"They?" The fish monster smiled a little.  
  
"Congratulations Fell. You have a son." He stood there, speechless.  
  
"A...son?" Fell couldn't help but smile at the news despite the situation his mate and newborn child were in.  
  
"Sans was actually asking for all four of you before I came down." She told him.  
  
"You can go see him if you'd like." The skeleton nodded and turned towards the kids.  
  
"We can go see your mom and the baby now. Just remember to use your inside voices." The girls nodded while his step-son disappeared, teleporting to the second floor. They followed Undyne upstairs and over to the first room on the left. She opened the door to the bedroom and let them go in first. Over on the bed lay another skeleton, his blue eyes holding a tired look in them, but brightened up when he saw the trio. His skull had some cracks on it, as did his collar bone and sternum.  
  
"Hey you three." He said, his voice soft and tired sounding. The girls ran over and climbed up onto the bed as Fell walked over and sat down on the edge.  
  
"Hey Swap." Said skeleton smiled and started to say something, but was interrupted by a coughing fit that shook his body. His breathing was raspy and uneven after he stopped and left him even more tired. Hex scooted closer to him with a worried expression.  
  
` "Mom?"` Swap opened his eyes a little and looked up at him with a tired smile.  
  
"I'll be fine sweetie. Would you three like to say hi to your new baby brother?" He suggested as Toriel came over with a small bundle in her paws. The girls smiled and nodded with Sarah eagerly holding her arms out so she could hold him first.  
  
"Be very gentle, my child." She said.  
  
"Okay." Carefully taking the bundle from the female boss monster's hands, Sarah held the newborn in her arms and smiled as she looked down at him.  
  
"He's so small and cute." After a few moments she handed him to Sasha, whose magenta-colored eyes immediately lit up with sisterly affection for her new sibling. The adults chuckled softly at her reaction as she handed him back to Toriel, who then went around to the other side of the bed.  
  
"Hex, would you like to hold him?" He hesitated for a few moments before slowly nodding and held out his arms. She carefully placed the newborn in his hands. Hex looked a little nervous as he held his baby half-brother. The infant's head was a little narrower than the rest of his family's, especially around his jaw, and he had tiny pointed teeth. His small, yellow, soul flickered weakly inside his ribcage, barely glowing.  
  
`"He's...um...okay, I guess?"`Swap smiled as he looked at his children.  
  
"Would you three like to name him?" He asked. Sarah and Sasha eagerly nodded and moved so they were closer to the infant.  
  
"He looks like a Herman to me." The youngest twin said. Sasha shook her head in disagreement.  
  
"No, I think he's more of a Cooper." Fell chuckled and looked over at Hex, who was quiet and had a thoughtful look on his face.  
  
`"What about....Onyx?"` They all had a surprised look on their faces, then they smiled and nodded.  
  
"Onyx sounds like a wonderful name." Swap told him and the older boy smiled a little as he looked at his mom. A small noise caught their attention and they looked at the infant in Hex's arms. His eyes were opening and little yellow pupils faded into view as he blinked a couple times. Onyx looked up at his brother with a curious expression on his face.  
  
"I think he likes you." The blue-eyed skeleton said, then reached over and carefully took the newborn from Hex. He gently cradled him in his arms as he smiled.  
  
"Hello there Onyx. I'm your mommy, and there's your daddy and sisters." Swap told him, adjusting Onyx so he could look at Fell, Sarah, and Sasha, then broke out into another coughing fit. Toriel quickly, and carefully, took the baby from him. A siren could be heard coming closer as the ambulance arrived. Soon Swap and Onyx were taken to the hospital.  


* * *

  
_Two skeletons, one of them being an infant while the other was an adult, sat under the stars in an open field of grass. The infant slept peacefully in the older skeleton's arms as they sang a lullaby._  
  
_"Cast away your worries, my love_  
_For tomorrow comes a new day_  
_Hold to me, you've nothing to fear_  
_For your dreams are not far away_  
  
_As you lay your head and you rest_  
_May your dreams take over my love_  
_Listen close, my son of the west_  
_For your destiny lies above_  
  
_Though the world is cruel_  
_There's a light that still shines_  
_In the darkest days of our lives_  
  
_When all hope seems lost_  
_And you can't find your way_  
_Think of me as you look to the sky_  
  
_Child mine, your future is bright_  
_For your father's blood's in your veins_  
_In dark times, I pray you will fight_  
_For the world will soon know your name." They smiled down at the baby as they stood up and started to leave, but stopped when they heard the sound of a portal opening behind them. The skeleton turned around as their gold cape fluttered in the soft breeze that began to blow and looked at the newcomer. It was another skeleton that looked almost identical except that they were wearing a blue hoodie, black shorts, and pink fuzzy slippers._  
  
_"He's not here and I don't know where he is either." The first skeleton said, as if they knew what the other one was going to say. They sighed and put their hands in the pockets of the hoodie, then looked at the infant._  
  
_"he's the father, isn't he?" The gold-cape-wearing skeleton nodded._  
  
_"Yes, he is." There was silence between the two for a few moments._  
  
_"He has promised that he won't hurt the child despite who his father is." They took a deep breath and looked at them with pleading eyes._  
  
_"Sire, will you not end this pointless cycle of hate and violence between the two?" The other skeleton closed his eyes and shook his head._  
  
_"this is something that has been going on for many years. you know how each of them feels about what they do and towards each other. he won't stop until he, or both of them, is dead. i'm sorry, but even i can't stop something like this." He looked down at the child in his arms._  
  
_"I know, but I can still hope can't I?" The blue-hoodie wearing skeleton gave a sad smile._  
  
_"do as you please. and good luck with the kid." He said, then walked through the portal and disappeared. The infant let out a small whine as they moved a bit._  
  
_"Shh. Shh. It's alright. It's alright." They quieted down as he gently rocked them and went back to sleep. Smiling, he lowered his head and nuzzled the baby's cheekbone._  
  
_"Sleep well, my child."_  


* * *

 

# Three years later...

  
  
He quickly hid behind the couch with a grin on his face as he listened to the footsteps of his brother as he looked for him.  
  
`"I know you're in here. Come on out."` The skeleton covered his mouth to muffle his giggle and carefully peeked out. His brother, Hex, stood a few feet away with his back to him. Unfortunately, he didn't notice the blue strings coming up behind him and let out a yelp as he was pulled out of his hiding spot.  
  
`"Ah ha! Found you Onyx!"` Hex said as the young skeleton was set down in his arms. Onyx crossed his arms and pouted.  
  
**"You cheat."** He told him as he reached up and bapped his brother's face. The older skeleton chuckled.  
  
` "Come on bro, don't be like that."` Yellow pupils looked up at him as Onyx still pouted.  
  
`"Better stop pouting. Otherwise..."` Hex grinned mischievously at the toddler.  
  
`"...the tickle monster will get you!"` He put Onyx on the floor and started tickling him. The three-year-old screamed with laughter as he squirmed under his brother's fingers, flailing his arms and legs as he tried to escape.  
  
**"S-s-st-t-to-o-op! Hahahahahahaha!"** Yellow tears glistened from the corners of his closed eye sockets as he laughed. After a while, Onyx found it hard to breathe and started coughing. Hex stopped when he heard the cough and realized he may have over done it with the tickling.  
  
`"Onyx, you okay?"` He asked as he reached out to help him up, but stopped when one of his half-sisters ran over.  
  
"Mom and Dad told you not to rough house with him like that!" Sasha said, glaring at him for a moment, as she helped Onyx sit up and gently patted and rubbed his back.  
  
**"I'm...f-fine...r-really."** The young skeleton told her between coughs. Hex glared back at his half-sister, then stood up and walked out of the living room. She huffed as she got to her feet.  
  
"I'll go get you some water." Onyx nodded and watched as she left, then stood up. He pulled himself up onto the couch and held onto the back of it as he stared out the window. The three-year-old let out a sigh and sat down as he waited for his sister to come back. Sasha walked over to him with a cup of water.  
  
"Here you go."  
  
**"Thanks Sis."** He took a few sips and set the cup down on the end table.  
  
"Feel better now?" Onyx nodded, then looked up at her.  
  
**"Can I go outside and play? Please?"** Sasha hesitated, looking down at the floor.  
  
"I don't know Onyx. We should wait until Mom or Dad come home first. I don't want you getting hurt."  
  
**"I promise I'll be really careful!"** The younger skeleton told her as she looked over at him.  
  
"Onyx, I..."  
  
**"Please?"** He begged, his pupils growing bigger as he did the puppy eyes. Sasha groaned softly, finding it difficult to resist the sad look her brother was making, and sighed.  
  
"Fine. You can go outside. But we're going to the backyard." She said.  
  
**"Yay! Thank you Sis!"** Onyx shouted as he gave her a hug, then slid off the couch and ran towards the back door. The older skeleton smiled and slowly shook her head.  
  
"The things I do for my little bro." Sasha smiled and jumped down, then followed her brother. They put on their shoes and stepped outside. He covered his face with his arms as he squinted at the bright sunlight, having never really been outside like this before.  
  
**"Woah! This is so cool! It's so bright! And warm!"** Onyx shouted, after his eyes had adjusted to the brightness, and looked around the backyard with wide eyes and a big smile. He went down the stairs and into the grass, getting down on his hands and knees to feel the ground. The three-year-old noticed something crawling in the grass and leaned in to get a closer look. Suddenly, it flew at him.  
  
**"Aah!"** He shouted as he fell backwards in surprise.  
  
"Onyx! Are you alright?" Sasha asked as she ran over. Her brother nodded and smiled.  
  
**"It was a big buggy!"** She smiled and chuckled softly as he got back up.  
  
"Oh my. Sounds frightening." Onyx held his head up a bit higher.  
  
**"I'll protect you Sis! I'll keep away the scary buggies!"** He said, grinning.  
  
"Oh really? But can you protect yourself from....the pinch bug?" Sasha asked, doing pinching motions with her fingers. His pupils widened and he scurried off. She giggled and followed him.  
  
"I'm gonna get you!~" Onyx laughed and hid in various places around the backyard as he tried avoid his sister. The eight-year-old just walked around, following him, pretending to lose sight of him, then come up behind and playfully roar before letting him get away and repeat the process all over again. They played like this for a long while. He got away from Sasha once again and was making his way over to another hiding spot when he suddenly felt light-headed. Onyx stumbled and fell to the ground, grunting as the wind was knocked out of him. His sister ran over and helped him up.  
  
"Are you okay, Onyx?" She asked and noticed the yellow glow coating his cheeks and face. He shook his head, feeling a little queasy, then felt himself be picked up and carried back into the house. Sasha set him on the couch and put a waste basket on the floor next to the couch.  
  
"Stay put. I'll be right back." Onyx gave a tiny nod and curled up as she left the room, then started to shiver. His sister came back with some blankets and set them on the couch, then had him lay on his back before covering him up.  
  
"You need to be more careful Onyx. You can't push yourself like that or you'll make yourself sick." She told him as she tucked the blankets around her little brother. He opened his eyes, looked at her, and smiled.  
  
**"But I had fun. Can we go outside again tomorrow?"** Sasha looked away for a few seconds before looking back at him and smiled.  
  
"After you get better and Mom and Dad are with us. Okay?" His eyes brightened and so did his face.  
  
**"Okay."** Onyx replied, giving a small nod, then curled up under the blankets and closed his eyes. She waited until he was asleep before letting out a small sigh, then climbed up onto the couch next to her brother and curled up.


	2. Shadows on the Horizon

Onyx and Sarah played around in the snow at the park with their Aunt Rose keeping an eye out. Sasha was at home trying to catch up on homework from the two days of school that she'd missed because of a cold. Hex was over at Jarrett's place playing video games and doing teenage boy stuff. The six-year-old boy laughed as they slid down a hill on top of their sled, throwing his arms up in the air with a whoop. Soon they reached the bottom and got off the sled. "Come on Onyx! Let's do that again!" Sarah said as she smiled. He eagerly nodded and started to follow her, then noticed something out of the corner of his eyes and looked over towards the forest. Onyx paused for a moment, then started walking towards the trees, curious to see what he had seen.

* * *

When she was half-way up the hill, Sarah stopped when she realized she couldn't hear her brother behind her and turned around. Her eyes widened when she saw him go into the forest and quickly ran after him.

* * *

He looked around as he rubbed his arms, starting to shiver a little. The boy kept catching glimpses of something moving out of the corner of his eyes as he tried to follow it. Onyx wasn't paying attention to where he was going and was soon lost. "Sarah? Aunt Rose?" The young skeleton called as he looked around, but there was no response. He gulped and continued to walk around a little as it started to snow and the wind picked up. After several minutes, Onyx was starting to find it difficult to walk as the cold was starting to seep into his frail body. He was shivering hard enough that he could hear his bones rattling.  
"Sarah?! Aunt Rose?!" Silence. The yellow-eyed skeleton started to sniffle and cry as he was now scared, then yelped as he tripped over some rocks that were hidden underneath the snow and went tumbling down the hill in front of him. He was knocked unconscious when he hit a large rock at the bottom of the hill and went still.

* * *

_A figure appeared over the top of the hill and looked down at the young skeleton. His eye sockets narrowed when he saw the boy's teeth, recognizing them. He walked down the hill towards him as his scarf flapped softly in the wind behind him. The figure stopped in front of the boy and raised a gloved hand as he gathered his magic....then lowered his arm as he sighed. He picked him up and teleported to a small clearing near the edge of the forest, close to the park, then set Onyx down in the snow. "I should leave before they notice my presence." The figure muttered quietly to himself, then teleported away._

* * *

Sarah turned around when she heard something and her eyes widened when she saw her brother in a small clearing, then ran over to him. "Onyx!" She shouted as she knelt beside him and gently lifted him into her arms. He let out a soft groan as he stirred a little, but remained unconscious. The female skeleton looked up when she heard their aunt's voice calling for them and teleported back to the hill.

* * *

As expected, Onyx had gotten a scolding for wandering off once he woke up. His parents grounded him for the next three days, meaning he wasn't allowed to go outside and play.

Later that night, the young boy woke up at around midnight as something pulled him out of his peaceful sleep. Listening carefully, he could hear a faint singing voice and went to the window to see if he could spot whoever was singing. He looked around, pressing his face against the glass, but didn't see anyone. However, he could just barely make out the words of the song.

_"Wishing on a dream that seems far off  
Hoping it will come today_

_Into the starlit night_  
Foolish dreamers turn their gaze  
Waiting on a shooting star

_But, what if that star is not to come?  
Will their dreams fade to nothing?_

_When the horizon darkens most  
We all need to believe there is hope_

_Is an angel watching closely over me?  
Can there be a guiding light I've yet to see?_

_I know my heart should guide me, but...  
There's a hole within my soul_

_What will fill this emptiness inside of me?  
Am I to be satisfied without knowing?_

_I wish, then, for a chance to see_

_Now all I need, desperately...  
Is my star to come."_ Onyx smiled as he listened, finding it relaxing to listen to. He sat down by the window and waited, hoping to hear the voice sing again, but he only heard silence. After a while, when he still didn't hear anything, he decided he should probably get back in bed and try to sleep. As he settled underneath the covers, he tried to sing the song in his head and soon fell asleep. The next morning, as he ate breakfast, Onyx couldn't get the song out of his head or stop thinking about the singing voice he had heard. He decided to ask his parents if they knew anything about it. Onyx went over to his mom and lightly tugged on his pants.

"Mommy?" Swap put his knitting down as he looked at his youngest son.

"Yes sweetie?"

"I heard someone singing last night. Do you know anything about it?"

"Hmm.....I'm afraid not. Sorry." He replied.

"Okay. Just thought I'd ask." The boy said, then jumped when he heard Sasha scream from upstairs which was followed by a several loud thuds. For a few moments there was complete silence, then...

"HEX! YOU ARE SO DEAD! YOU HEAR ME?!" Sasha shouted as she slammed a door open. Swap sighed and got to his feet before heading over to the staircase, then went up to the second floor to see what the matter was.

* * *

Swap froze when he reached the landing and saw his eldest daughter's face. Marker had been scribbled all over her skull in different colors. Sasha was breathing heavily and shaking while her eyes were glowing with a mix of fear and anger. "Sasha, what happened?" He asked once he snapped out of his shock and hurried over to her.

"There were spiders! In my bed! Then something tripped me and I fell! Then I get up and glance over at Sarah's desk mirror and saw my face like this!" She shouted.

"Shh. Shh. Sasha, calm down. Take deep breaths." The older skeleton said as he crouched down and gently grabbed her shoulders. Sasha gave a few shaky nods and took deep breaths to calm herself down. "Good girl. Now let's go downstairs and see if we can get that marker washed off."

"I don't want them to see me like this!" She exclaimed.

"Alright! Alright. Calm down. We'll use the bathroom in the guest bedroom instead." He told her, then lead her to the said room. It was difficult, but after a lot of scrubbing he managed to wash the marker off of his daughter's face. "There. All done." Sasha looked at herself in the mirror to make sure that all the marker was gone, then nodded.

"Thanks Mom."

"You're welcome sweetie." Swap said and patted her skull. "When your father and Hex come back, I'll make sure to have a stern talk with that boy and have him clean up." Sasha nodded.

"He better get rid of all those spiders." She muttered, shuddering as she wrapped her arms around herself. "I hate them so much."

"I'll make sure he does. Now let's go downstairs and I'll make you some blueberry pancakes with chocolate chips." The blue-eyed skeleton told her. Sasha perked up at this as she smiled and nodded, then followed her mom downstairs.

* * *

Fell thanked the guard when they opened the cell door for them. "Whoa! Hey, get back here kiddo." He said as he grabbed the back of his step-son's shirt. The sixteen-year-old huffed and wiggled as he tried to get out of his grasp.

"Let go! I don't get to see Dad everyday, so I want to make every minute count." Hex told him.

"What's the magic word?" He looked at the older skeleton and scowled, then huffed as he looked away.

".....please." Fell nodded and let go. Hex crossed his arms and walked into the cell room with his step-dad. His smile quickly came back with he saw the black skeleton inside. "Hi Dad!" The larger skeleton lifted his head up and smiled when he saw the teenager, then started to sit up.

"Hey kiddo. Hey Sw-....oh. It's just you." Error muttered when he saw the gold-toothed skeleton.

"Nice to see ya as well." Fell grumbled as he walked in.

"Aaannnddd we're off to a wonderful start." Hex mumbled sarcastically as he looked between the two.

"Just do what you normally do. So don't mind me." Fell told him as he sat down by the door. He nodded before turning back towards his dad, who sighed a little before smiling at him.

"Why the sigh? Are the guards being assholes again?" Error shook his head as he chuckled.

"Nah. Not really."

".......upset that I had to bring him with me instead of Mom?" The teenager asked as he pointed at Fell.

"....a little." The older skeleton admitted. Hex chuckled a little.

"Sorry Dad. Maybe next time."

"Eh, it's fine. So how are things going?" Error asked. He shrugged a little.

"Rather boring to be honest. Especially with school. Sasha is still annoying as ever and I spend most of my time with Jarrett or Onyx." Hex replied.

"How is the little guy doing?"

"Still sickly. Doesn't help that it's winter time and that's when he gets sick the most. But right now he's doing fine." The black skeleton nodded as he listened.

"Anything else?" He was silent for a few moments as a grin slowly spread across his face.

"......I miiight have left a surprise for Sasha before we left. I just hope she hasn't woken up yet." Hex replied, snickering as he imagined his half-sister's reaction. Error chuckled and pulled his son into a hug. They both ignored Fell's groan.

"So what kind of surprise did you leave?"

"Practically filled her bed with spiders, drew on her face, and left marbles on the floor for her to trip over. I thought about putting snakes in her closet, but I couldn't find any." He told him, causing the larger skeleton to laugh and soon joined in.

"You're gonna be in a lot of trouble young man." Fell said as he looked over at the two. The teenager just shrugged.

"Just ignore him. Besides, I doubt Swap will punish ya anyway." Error said.

"He does, but it's nothing major. Usually cleaning up the prank and a few days of being grounded." He replied. The older skeleton and the two of them chatted a while longer, then looked up when the door opened.

"Time's up." The guard told them. Fell looked up and nodded, then got to his feet.

"Come on Hex. Let's go." Hex looked at him and frowned as he whined.

".....alright. Bye Dad." He said as he hugged the older skeleton.

"Take care of yourself, kiddo."

"I will. See you next time."

"See ya." Hex and Fell left the room and went through the portal back to the house. Once they were through, Fell closed it behind him. Sasha was sitting at the table eating breakfast, though she smirked a bit when she saw her half-brother.

"Dang it. I missed it." The teenager cursed under his breath when he saw her and pouted.

"Mom! Hex is back!" She called over her shoulder. Swap stepped out of the kitchen and looked over at his mate and eldest son. Fell instantly recognized the look in Swap's eyes and sweated a bit.

"Welp. I'm gonna go take a nap." He said and went upstairs.

"So how was your visit?" The blue-eyed skeleton asked.

"Great actually, and even though Dad didn't say it I'm sure he'd want me to say he told me to say hi." Hex replied as he looked up at his mom.

"That's very thoughtful of him." He said.

"Yeah. Is Onyx upstairs?" The younger skeleton asked and glanced towards the stairs. Swap nodded. "Guess I'll go up then." He said and headed towards the stairs.

"Don't forget to clean up the mess you made in your sisters' room." The blue-eyed skeleton told him.

"What mess?" Hex asked and looked over at him.

"You know what I'm talking about mister."

"I didn't make a mess in there, except on her face...well, more of a mess on her face than it already is." He replied. Swap gave him the look.

"Do not make me repeat myself, young man."

"Fine, fine. I'm going." Hex mumbled as he walked to his sisters' room.

"I'm not finished talking with you yet." He said as he turned his eldest son's soul blue and pull him back over. "Do you remember the discussion we had a few days ago about you picking on Sasha? While she tries to get caught up on her school work?" Hex groaned and nodded.

"My memory's not that bad. Of course I remember."

"Then you should have remembered that you promised me that you'd leave her alone until she got caught up, otherwise your stuff would be taken away and you'd be grounded for a week."

"I didn't think you were serious about that!" He exclaimed. Swap crossed his arms. "Besides, she's stressing over nothing." The teenager added and shot a quick glare at Sasha.

"Semester finals are coming up and I need to get my school work done so I can focus on studying for the tests." She said as she finished eating and took her dishes over to the sink. Hex rolled his eyes at that and crossed his arms.

"Speaking of tests and finals, you should be studying for yours as well." Swap told him as he set Hex back down.

"It's just a waste of time." The younger skeleton said.

"If you pass your finals with at least a C in each one, I might consider talking to Classic about letting your father join us for Christmas this year." He added as he turned around. Hex froze for a moment before looking over at his mom.

"Say what?"

"You heard me. You pass your finals, I talk to Classic about letting your dad come over for Christmas." The older skeleton said, smiling a little.

"So you're basically making me choose between my dad and my morals. That's evil." Hex said.

"So what'll it be?"

"Buuut, if Classic says no then I did that all the work for nothing." He said. Swap sighed.

"Alright then. Guess your dad won't be coming over then. Shame really."

"And people have the guts to say Dad's the bad one..." Hex muttered. He chuckled.

"Let's just say I've had plenty of practice back from when I'd go over to Fell's AU to visit him." The younger skeleton growled in annoyance.

"Like a real visit? Not just the few minute stuff like whenever I go to Limbo?"

"Hex, we are not discussing this." Swap said firmly.

"....Ugh,fine." He muttered. The older skeleton sighed.

"Your school stuff is still in your room and on your desk." Hex grumbled something under his breath that sounded like a curse word before he teleported upstairs. Onyx looked up when his brother appeared in their room. "And you better remove all those spiders from your sisters' room! Or you don't get any desert tonight!" Swap called.

"What's for desert?!" Hex called back.

"Blueberry pie." Swap replied.

"...Fine." He replied and picked up a box from his and Onyx's room floor.

"...I told you you shouldn't have pranked Sasha." Onyx said. The older skeleton rolled his eyes and walked to the girls room.

* * *

He sighed and curled up a little. Onyx could hear Sasha and Hex arguing down the hall....again. Why did they have to fight so much? The boy curled up under the blankets and put a pillow over the sides of his skull, but he could still hear them. So he teleported downstairs and into the living room where he couldn't hear them. Onyx wished they would stop, but somehow he got the feeling they never will and it made him unhappy.

**Notes for the Chapter:**

> FFFFFFIIIINNNNAAAAALLLLLLLLLYYYYY!!!!!!! I have this chapter up!!!
> 
> Sooo......I wonder who the mystery person in this chapter is. Or who the mysterious singing person is.
> 
> Jk. I already know who they are, but I'm not telling~
> 
> Also, the part with Sasha having marker on her face is actually something that happened to me when I was in kindergarden or first grade, don't remember exactly. But I learned a lesson that day:  
> Never trust fifth graders that want to put "make-up" on you.
> 
>  
> 
> Swap, Fell, and Error belong to their respectful owners.  
> Hex belongs to Miiv12  
> Sasha belongs to ShinySmeargle  
> Onyx belongs to me


	3. Meeting of Two Stars

The seasons passed by for the family of six and the arguing between Hex and Sasha didn't get any better. In fact, it seemed to get worse and it was starting to affect Onyx. To get away from it, he'd go to Undertale using the machine in the basement and spend time with Classic. After a while, he started to call the older skeleton Uncle, which Classic didn't really mind. They never did much except just hang out and chat a little.  
  
    One day, while the two were walking through Waterfall, an eight-year-old Onyx stopped and looked at Classic. "Uncle Classic?" He stopped and looked down at him.  
  
    "yeah kiddo?"  
  
    "Why do the other Sanses not like my family?" Classic's eyes widened a bit, caught off guard by the unexpected question. He looked to the side and rubbed the back of his skull.  
  
    "well....it's not your family personally. it's more that they don't like your brother and his dad."  
  
    "But why?"  
  
    "oh boy. um...well you see, Error did lots of bad stuff before he met your mom. he hurt a lot of people and destroyed their homes. some of the survivors still remember the terror they felt and hate him for taking away their loved ones. a lot of them fear that Hex will end up the same way." The older skeleton explained. Onyx frowned.  
  
    "But big brother would never hurt someone on purpose! Yeah he does do some mean things, but he doesn't hurt people." He told him.  
  
    "i know kiddo, but they don't see him the way you do." Classic replied, then noticed Onyx frown and lowered his head. The older skeleton crouched down and placed a hand on his shoulder. "tell ya what, normally i hate making promises, but for you i'll make a special exception. i promise that i'll do what i can to keep your brother safe from harm and make sure nothing bad happens to him." The boy looked up at him, then held out his pinkie.  
  
    "Pinky promise?" Classic smiled and wrapped his pinkie around Onyx's.  
  
    "i pinky promise." Onyx smiled and hugged him.  
  
    "Thank you Uncle Classic." Said skeleton chuckled and patted his back.  
  
    "you're welcome kiddo." He said, then pulled out his phone to check the time. "we better head back. don't want your parents to worry."  
  
    "Okay." The two headed back to Snowdin and Classic set the coordinents in the machine, which opened a portal to Underswap.  
  
    "take care, alright?" Onyx nodded and waved as he went through the portal. Once he had gone through, Classic closed the portal and left the basement.  
  


* * *

  
    Later that night, Onyx had a hard time falling asleep and lay in bed as he stared up at the ceiling. Everyone else was fast asleep and he didn't want to bother them, so he tried to sleep as best he could. After a couple hours of restlessness, Onyx got up and went over to the window before sitting down. Subconsciously, his hand started to move to his wrist and start to scratch and pick. He stopped when he scratched a bit too hard, causing him to flinch from the pain, and looked down. His wristbones were started to look chipped. Onyx frowned and looked over at his brother, who was fast asleep. He didn't know why, but he'd been feeling this urge for a while now and he didn't know what to do. The boy was scared to tell his parents in case they got mad at him. He sighed and laid down, eventually falling asleep.  
  
    A few weeks passed, and Onyx's birthday arrived. The family went out to eat for lunch at Grillby's Bar and Grill and got a table big enough for the family of five, plus Edge, Papyrus, Rose, and Muffet. "Why couldn't we have gone to Grandma's place instead?" Hex asked as they all sat down.  
  
    "Because your brother chose here for us to eat." Swap told him.  
  
    "Plus, dearie, my store is a bakery. Not a restaurant." Muffet added. The nineteen-year-old muttered something under his breath as he looked at the menu. Onyx looked at his brother.  
  
    "....we're going to stop by later to get my birthday cake." He said. Hex looked at him and smiled.  
  
    "I know bro. You're gonna love the cake Grandma made." The boy smiled and looked back at the menu. After a while, they ordered their food and chatted while they waited. Onyx colored in the coloring book he had brought with him while they waited for their food. The twins, Sarah and Sasha, were chatting about school and school gossip. Soon their food arrived and they started to eat.  
  
    "It only seemed like yesterday that Onyx was just a tiny baby bones." Swap said, smiling. Onyx blushed a little. "I can't believe it's been nine years since I gave birth to you." Fell smiled and nodded.  
  
    "I remember that day. You were so tiny you could fit inside a baseball cap when curled up."  
  
    "Mom....Dad....not in public." The nine-year-old whined, pulling up his mask to hide his blushing face. Swap chuckled a bit.  
  
    "Sorry sweetie. I was just feeling nostalgic is all." Onyx gave a small nod, then pulled his mask back down so he could eat.  
  
    "Mommy! That kid has pointy teeth!" The boy skeleton froze and looked around, then saw a human kid pointing at him. He watched as the mom pulled the kid away and hurried them along while looking at him nervously. Onyx frowned and lowered his head as he pulled his mask back up and hunched over a little, suddenly not feeling that hungry anymore. The rest of the family frowned, having noticed the exchange. Fell sighed and looked at his son.  
  
    "Come here kiddo." He said, patting his lap. Onyx hesitated for a moment, then got down and went over to his dad. The boy crawled up onto his lap and leaned against him while the older skeleton wrapped an arm around him. "There we go. I got'cha." Fell told him, holding Onyx close. He knew that having pointy teeth bothered Onyx, since it made other kids and their parents wary of him. The red-eyed skeleton knew that feeling all too well, as he had had to deal with it when he moved to the surface with Swap and the other monsters of this AU.  
    Hex glared at the kid's mom, feeling rather tempted to scare her, but knew that doing so would get him in trouble in more ways than one... He huffed and leaned back in his seat as he took a bite of his chicken. Hopefully Onyx would be cheered up once he saw his presents. After a while, they all finished eating and paid for the food before leaving. Onyx went over to his Uncle Papyrus and held his arms up. The tall skeleton looked down at him and smiled, then picked him up with his magic and set him on his back. "There you go kiddo."  
  
    "...thank you Uncle Pap." He smiled a bit more.  
  
    "Any time." Papyrus said, then followed the others as they headed towards Muffet's bakery. Once they reached it, Muffet went inside to get the cake. She stopped and looked at her youngest grandson.  
  
    "Would you like a lemon tart along with your cake, dearie?" Onyx smiled and nodded.  
  
    "Yes please." The spider monster nodded and went inside. A few minutes later, she came back out with a cake box and a paper bag. The family headed to Swap and Fell's house for Onyx's birthday party.  
  


\------------------------

  
    The whole family laughed as they played games, like Twister, Charades, Uno, and had fun. Soon it was the big moment: opening the birthday presents. Onyx's face lit up when he saw the pile of gifts from his family. He tried to decide which one to open first, then grabbed one that was from his parents and opened it. The boy pulled out an action figure of a cowboy. "Cool! It even comes with a lasso and horse! Thank you Mom and Dad!" Swap and Fell smiled.  
  
    "You're welcome sweetie." Onyx set the action figure behind him, then grabbed the next present. This one was from Edge and it was a red scarf.  
  
    "I know you won't wear it until wintertime, but I thought you would like it nonetheless." The taller of the two Papyruses said. Onyx got up and hugged him.  
  
    "Thank you Uncle Edge." He said, then draped the scarf over his shoulders while he opened the rest of his presents. From his Aunt Rose he got plush toy dog, a hand-knitted sweater from Muffet, a Hot Wheels car from Papyrus, a joke book from Classic, who had sent his best wishes to the boy, and a purple and yellow-striped shirt from Sarah. Onyx looked around for his presents from Hex and Sasha, but didn't see any and frowned as he looked at the two.  
  
    "We wanted to save our gift for last. For once, we decided to work together to get you a special birthday present." Sasha told him and pulled out a flat box about the size of her hand, then handed it to him. Onyx was surprised by this as he took the box and carefully unwrapped it. He pulled off the lid and his eyes widened in awe. Inside was a gold pendant in the shape of a sun with an amber gem in the center. The yellow-eyed skeleton carefully picked it up and looked at the pendant more closely. Onyx was completely speechless, though he didn't know if it was from the fact that his brother and sister, who constantly argued, had worked together to get this for him or if it was from how beautifully designed it was.  
  
    "The pendant is magic. It'll protect you from danger if you give it a bit of magic." Hex told him as he smiled. There was no reply from the nine-year-old as he kept staring at the gift. After a bit, Onyx smiled and looked at Sasha and Hex with tears in his eyes.  
  
    "I love it. Thank you." He said. They both smiled, glad that he loved their gift. The boy put the pendant on and smiled, feeling his soul pulse happily. "I'm never going to take this off. Except for when I have to wash or want to go swimming." Swap nodded.  
  
    "Sounds good." Onyx smiled for the rest of the day and for a long time after that, as his sister and brother weren't arging that much any more. Unfortunately, peace never lasts forever. Hex started pranking Sasha again, which caused her to grow angry. In turn, the two started arguing again. If anything, it was even worse. Onyx started to hide even more when they started to exchange harsh words with each other. He started to pick and scratch at his scapulas, as well as wear his mask nearly 24/7.  
  
    The only time he ever got any peace was when he was over in Undertale with Classic, or hanging around a giant oak tree that he had found in the park a few years ago. But he knew that he would have to go home sooner or later and be forced to endure any arguing that was going on. Onyx hated it and he wished there was someway he could stop it...  
  


* * *

  
    About a year passed by and the arguing did not cease. It tore at Onyx, hearing his brother and sister argue like this after they had worked together to give him his pendant. The ten-year-old was downstairs, trying to watch TV, but then he heard his sister start to shout upstairs and soon heard Hex shout back. Onyx gritted his teeth, trying to ignore it. After a bit, he started to tremble and feel nauseous. He started to grow scared and dark thoughts started to creep into his head. Soon it became too much and he got up from the couch. He headed to the basement door and opened it, intending to head to Undertale to get away for some peace. However, he forgot that his mom had used the machine the day before and didn't change the coordinents for the portal when he turned it on. The portal opened up to a forest and he stepped through without hesitating.  
  
    Suddenly he found himself falling through the air and branches scratched at his face and clothes as he cried out. Fortunately, none of them snagged on his pendant, but they did with his mask and hat and tore them away. He hit the ground with a thud and everything went black...  
  


* * *

  
     _A young skeleton looked up when their animal companion, a tall monster hybrid of an alpaca and sheep with shimmering blue and white fur, lifted it's head up with perked ears. "Do you hear something?" The creature nodded and got up, then ran off. They sighed and pulled up their knees to their chest. The young skeleton wore a mint green onesie with a yellow and black star on the front and a pale blue cloak that looked like it held the night sky within it's fabric. They looked up at the trees with light blue eyes that had white stars for pupils and smiled when they spotted some birds flying around._  
  
  
    A few minutes later, they heard footsteps and looked up to see the hyrbid monster return with what looked like a red baseball cap and a blue handkerchief. They tilted their head in confusion when they saw the items and carefully took them from the hybrid. "Where did you find these?" The monster let out a quiet bark and nodded their head in the direction they had come from. The young skeleton looked over and frowned a bit. "Let's go see if we can find their owner." They said and started to float down the trail with the hybrid following.  
  


* * *

  
    Onyx groaned as he regained consciousness and slowly sat up. He rubbed his skull and winced when he felt a crack on it. The boy slowly got to his feet and looked around, then started to grow scared when he didn't recognize where he was at and saw that it was dark out. "W...where am I?" He said to no one, then realized that he didn't have his mask and hat on and started to freak a little. Onyx jumped when he heard a branch snap and started to run, scared that it might be some wild animal. He turned to go around a rather large tree when he suddenly ran into something and fell backwards. "Ow!" The boy cried out as he crashed to the ground  
  
    "Oh my! I'm so sorry! Are you alright?" A voice asked. Onyx looked up and froze as he stared at the star-eyed skeleton in front of him, shocked speechless by their beauty. His mouth moved as he tried to reply, but nothing came out. The other skeleton frowned a little and crouched in front of him. "Are you okay?" They repeated. He snapped out of it and nodded.  
  
    "Um...y...yeah..." Onyx replied. The star-eyed skeleton smiled and held out their hand. The boy hesitated for a moment, then took their hand as they helped him to his feet. "Uh...t-thanks." He said, blushing slightly as he rubbed the back of his neck. Onyx felt himself blush even more when the other skeleton smiled.  
  
    "You're welcome. Oh, are these yours?" They held out his hat and mask.  
  
    "Oh, yeah. Thanks." The boy said as he took the items and put them back on, though he pulled his mask up a bit higher to hide his blush. "Um....c...could you...tell me where I'm at? I, uh...I-I'm not from here and...and I don't recognize this place." He told them. The other skeleton smiled and nodded.  
  
    "This is Dreamtale." They replied. "...are you lost?" Onyx hesitated, then nodded.  
  
    "...yeah."  
  
    "I could help you get back home if you'd like." His eyes widened a little.  
  
    "R-really?" The star-eyed skeleton nodded, then held out their hand.  
  
    "My name is Uni. What's your's?"  
  
    "Onyx. Onyx Sans." He replied as he took their hand and shook it.  
  
    "Onyx...that's a nice name." The yellow-eyed skeleton blushed a bit more.  
  
    "T-thank you." He looked up when a strange alaca-sheep hybrid monster walked up and stared down at him. Onyx backed up a little as he let go of Uni's hand.  
  
    "It's alright. He won't hurt you. This is Baku. He's my pet." Baku leaned over and sniffed the boy, then snorted and pulled back. He gave a small nod, though he was still a little intimidated by Baku's size. Uni motioned for the hybrid to lay down and he obeyed. "I'll take you home now." They said before climbing onto his back. Onyx nodded and climbed up behind them.  
  
    "Woah. His fur is really soft." He said. Baku lifted his head up, as though proud. Uni smiled and nodded.  
  
    "I like to snuggle up against him when I go to sleep." They told him. "Oh, by the way. Do you know the name of the AU you're from?"  
  
    "Yeah, it's Underswap." Onyx replied. The star-eyed skeleton nodded and turned back to Baku.  
  
    "Baku, take us to Underswap please." The hybrid nodded as he got up, then started to walk. Soon he was trotting along and started to rise up into the air. Onyx tightened his grip as he held onto Baku's fur to keep himself from falling off. A portal opened up in front of them and they went through it. They came out above the park near the city and it was still day time. His eyes widened as he looked around. "Is this right?" Uni asked as they looked back at him. He nodded and looked around for a familiar landmark.  
  
    "Over there." Onyx said, pointing to a large oak tree. "You can drop me off there." They nodded and had Baku head for the tree. A few minutes later, they landed and the hybrid laid down so they could get off. The boy slid off and landed on the ground, then turned to face Uni. "Thank you for bringing me home."  
  
    "It was no problem, really." They replied with a smile. Onyx felt himself blush again and felt his soul skip a pulse. "I should get going."  
  
    "O-okay. Um...can we...can we meet again?" He asked. Uni paused as they started to climb back onto Baku's back and looked at him, then smiled.  
  
    "Sure." The boy smiled and blushed a bit more.  
  
    "G-great! Uh...h-how about here next weekend?" They nodded.  
  
    "Sounds good. I'll do my best to try and remember that." The star-eyed skeleton told him, then climbed onto Baku and held on as he stood up. "See you later Onyx." Uni said as the hybrid started to walk away.  
  
    "Bye Uni!" He called back and waved. The boy stayed put as he watched them leave and disappear through a portal. Onyx turned and started to head home, excited for when he would see Uni again.

**Notes for the Chapter:**

> Hex and Uni belong to Miiv12  
> Sarah and Sasha belong to ShinySmeargle  
> Onyx and Rose belong to me.
> 
> Underfell Sans and Papyrus, Underswap Sans, Papyrus, and Muffet belong to the AU Community, Undertale Sans belongs to Toby Fox.

**Author's Note:**

> Hmm.....wonder who the mysterious skels are? And who could they be talking about? And why did I put that little scene in there? Who knows? Oh wait....I do and I'm not telling~ But they will play an important part later on in the story. ;3
> 
> The only character in this chapter that I own is the little babu Onyx!  
> Hex belongs to Miiv12 while the twins, Sarah and Sasha, belong to ShinySmeargle.  
> CHECK US OUT ON DEVIANTART! Seriously! It'll really help! Cause the three of us are artists! And pictures are worth a thousand words as they say!
> 
> Expect LOTS of drama to come up in later chapters, cause this is the part of MotS where shit. Gets. Real.


End file.
